Automatic telephone system



June 16, 1931. H, WARWICK AUTOMATIC TELEPHONE S-YS-TEM' 3 Sheets-Sheet l ELI Var i0 7 Filed May 9, 1925 H. L. WARWICK AUTOMATIC TELEPHONE SYSTEM June 16, 1931.

. Filed May '9. 1928 3 Sheets-Sheet 2 June 16, 1931. H. WARWICK AUTOMATIC TE1LEPI-IONIEI SYSTEM 3 Sheets-Sheet 5 Filed May 9, 1928 m l a W W W L H attoz e1 Patented June 16, 1931 UNITED STATES HAROLD LYNWOOD WARWICK, OF FORT WORTH, TEXAS 7 AUTOMATIC TELEPHONE SYSTEM Application filed May 9, 1928. Serial No. 276,357.

vide in a device of this character a novel and improved switching mechanism controlling the sequence of operations of the ringing and registering apparatus after connection with the called party has been put through.

VA still further object of the invention is the provisionin a device of this character 29 of an arrangement and construction such that the operation of the telephone is not interfered with and a mechanism provided whereby a call may be put through in its regular orde'rwithout regard to the fact that a previously calling party has neglected to complete the sequence of operations neces sary to the recording of the number from which he is calling.

A stillfurther object of the invention is to provide an apparatus of this character which may be very readily installed and which, in its installation, requires that the attachment of a few wires which, as they may be readily connected, permit the installation without anyappreciable interruption of the service. These and other objects I attain by the construction shown in the accompanying drawings; wherein for the purpose of illustration is shown a preferred embodiment of my invention and wherein Figure 1 is a diagram illustrating certain portions of an automatic telephone system and two subscribers lines connected thereby, one of the lines being shown as adapted for connection with my apparatus;

Figure 2 isa diagram of my recording EXP. paratus as connected to'the subscribers station in which the recording mechanism is 5 0, shown in side elevation;

Figure 3 is a lan of the recording mechanism partially roken away; j

Figure 4 is a detail sectional view illustrating the cooperation of the brush with the contacts of the sequence switch. 7 Y Y v In the drawings, I have illustrated two subscriber stations, one of which, indicated at 10, will hereinafter be identifiedmas the calling partys station 10 and is not shown equipped with recording apparatus-and the other of which, generally indicatedat 11, will hereinafter be referred to asthe called partys station and isequipped with recording apparatus, diagrammatically shown in Figure 2. p

I have also fragmentarily illustrated the central station as'regards those. portions thereof necessary to an understanding of the invention. Leading from the station 10 are line wires 12 and 13 which, through the usual 7 wipers and bank contacts, generally designated 14, are connected to the line relay 15 of a connector'switch mechanism of the usual type. a

This line relay is the primary operating and control member of the connector switch" and functions in its usual manner in such systems. The complete operation of this. switch is not here given, it bein suflicient to state that if the called line is found idle, a wiper closing relay 16, is energized, connecting the wipers and bank contacts 17 to line wires 18 and-19 of the called station 11. At the same time, a. ringing operation is initiatedthrough a. circuit including. the usual ringing switch 19a which, in the normal manner, causes intermittent ringing operation of the bell 20 at the calledstation. This ringing circuit includes one winding- 21 of a double wound, relay R, generally known astheringing cutofi relay but fails to cause. any actuationof this relay due to a copper sleeve (not shown) which is applied to the end of the core to prevent operation under these conditions. If the :called party removes his; receiver 22 from, the switch hook'23, contacts, 24, and 25are connected, setting up. a path for the direct current of abattery 26, which may be traced as follows: From thebatteryground throughthe battery 26, windin 21 of the ringing cut-off relay, contacts 2 and 28, wire 29, the bank contacts 17, wire 18 through a path, hereinaftermore specifically described, to the calling apparatus, the contacts 30, over wire 31 to the transmitter, from the transmitter through the hook switch 23, contact 24 and the usual induction coil winding 32 to the line 19 and through the bank contacts 17 and wire 32a to contacts 33 and 34 and the ground. This causes the ringing cut-01f relay to be operated and the armature contacts '28, 34, 35 and 36 thereof to close uponthe contacts 37 38, 39 and 40 respectively.

The closing of. the contacts 36, 40 looks the relay B through its second winding 41, while the closing of the cont-acts 34 and 37, and 28, 38, switches the called station loop from ringing to talking position and performs-certain other operations unnecessary to an understanding of this invention. This places the subscribers in a position to carry on conversation in the usual manner.

In accordance with my invention, I provide an apparatus including a main controlling or sequence switch, generally designated 4, including an oscillating switch arm 42 having a wiper 43 which, as the arm is progressively advanced successively electrically connects pairs of contacts which are designated as the first to the twelfth pairs.

A spring 44 gives bias .to this arm normally maintaining its wiper in engagement with the first pair of contacts. The hub of the arm has a ratchet disk 45 and associated with this ratchet disk are operating and holding pawls 46 and 47. The operating pawl 46 is carried by one arm of a bell crank lever 48, the other arm of which forms the armature of an electro-magnet 49, release of which is delayed byapplication of a. copper collar to its core. This armature is provided with a jack arm .51 which, when the armature is attracted, opens the contact'springs 52. The

operating pawl acts to advance the switch arm 42 as the armature is released. The

' 'pawls'46 and 47 are withdrawn from engagement with the ratchet by the armature 53 of an electro-magnet54 which is also constructed to provide a delayed release. a

This armature has a jack arm 55 which,

when the armature is attracted, opens the contact springs 56. I also provide a.pluralit of rotatable number wheels 57. Five nnm er wheels and their operating "mechanism are provided, but since each, of these structures is a duplication, only one thereof has been fully illustrated and the remainder generally designated.

v The' number wheel 57 bears upon its periphery a series of numbers or characters,

upon one arm of a bell crank 62, the other arm of which forms the armature of an electro-magnet 63. The pawls are withdrawn from engagement with'the' number wheels by the armature 64 of an electromagnet 65 constructed to provide a delayed release. This number wheel has associated therewith a bias spring, designated at 66.

Associated with the number wheels is a A printing and release magnet 67 whose armature 68 is in the form of a lever bearing a pressure bar 69 forforcing a strip of paper 70 fed between it and the number wheel into engagementwith the number wheel. This strip passes between feed and pressurerollers 71 and 72. The feed roller 71 has a ratchet hub 73 with which are associated actuating and holding pawls 74 and 7 5. The actuating pawl 74 is carried by an extension 76 of the armature 68. A local battery 77 is provided together with a polarized'relay 78 for controlling the output thereof. A second relay 79 is provided which operates to release the -mechanism and clear the line as will be and to one of the contact springs 52. From the contact 30, to which the wire 18 is nor-.

mally connected, a wire 82 is extended and connected to the second contact of the electro-magnet 79, as at 83, and to the second contact of the first pair of contacts of the switch 4, as atf84'. r i

The bell of the station ,11 is connected in parallel with the relay 78 by wires 85 and 86,of which the wire 86 is connected between the bell and the usual condenser connection between this bell and wire 18. This wire 86 is connected by a wire 87 with' one of the sixth pair of contacts of the switch 4s The second contactof this pair is con? nected by a wire 88 with one of the spring I contacts'56 and the second of these contacts 56 is connecte by a wire 89. Y

(The armature contact 90 of the polarized rel,ay.78 is connected to the positive -termi--,

nal of the battery 77. The output terminal 91 is connected by a wire92-with one contact of each of the seventh, eighth, ninth, tenth,

with the,second contact" 52 and-eleventh pairs of contacts of the switch 4, and the contacts 91 and 91a are connected to one another, as at 916... As the complete connections of the eighth to eleventh pairs of contacts are not disclosed, it

will be understood that the connections for the remaining contacts of these pairs are the same as those described for the second contact of theseventh pair. From the sec ondcontact of the seventh pair, a wire .93 is led to one terminal of the'electro-magnet 63. From the second contact of the coil of the electro-magnet 63, a return wire 95 is connected to the negative terminal of the local battery -77. From the wire 92, a wire 96 leads to one terminal of the electroand is connected to one terminal of the through the wires 92, 96., 97 and 95. Due

electro-magnet 67 and to the wire 95. From the positive contact of the battery 77, a wire 98 is led to one contact of the twelfth pair of the switch 4. From the second contact of this pair, a wire 99 is led'to the second terminal of the electro-magnet 67. The

armature of this electro-magnet has associated therewith contact springs 100 which are closedby attraction of the armature and one of these-contact springs is connected to the wire'98.

The second contact of this pair is connected in parallel with one terminal of each of the electro-magnets and 54 by wires 101 and 1.02. The second contact of the electro-magnet 54 is connected to the return wire 97 as indicated at 103. Between the wire 98 and one of the output contacts 104,,

a wire 105 is connected, while the wire 101 is connected to the second of these contacts.

by'a wire 106. r

Assuming that the call has been put through from the calling tothescalled station and the switch arm 42 to be in its normalposition in which the wiper 43 electrically connects the contacts of the first pair,

ringing current intermittently delivered to the called station will follow a path as follows: Through wire 85, relay 78, and wires 87 and 86, condenser18a and wire 18 to the bank contacts, thus placing the relay 78 in parallel with the coil of the bell apparatus 20. The armature of this relay 78 will vibrate in the same manner as the armature of the bell, thereby alternately opening and closing to supply current from battery 77 to the operating "coil 49 of the switch 41 to the copper acket or collar 50 placed upon the core of this magnet,.the armature thereof will not vibrate but will be held down until the ringing period has terminated. As this period terminates, the armature 48 returns to its-normal position, advancing the arm 42 -to the second pair ofcontacts' The second to fifth pairs of contacts inclusive are dummies, simply providing a track over which the wiper 43 of the switch operates and accordingly the above operation continues until the arm positions the wiper 43 upon the sixth pair of contacts. Engagement of the wiper 43 with. this pair of contacts'setsup a direct current-path from the battery 26 as follows:

From this battery through the lesser winding 21, contacts 27 and 28,-the wiper contacts 17,v wire 18, contacts 52, wire 89,

contacts 56, wire 88, the sixth pair of sequence switch contacts, wire 87, windings of the relay 7 8, wire 85, wiper 17, wire 32a and contacts 33 and 34 to the ground. This causes the relay 7 8 to come into action, closingthe circuit of the operating magnet 49 and, at the same time, causing operation of theringing cut-oii relay R, closing contacts 40 and 36 and breaking the direct current path of the battery.26 through the smaller P .winding 21; Since attraction of'the armature 48 of the electro-magnet 49 opens the circuit of this operatingmagnet at 52, the

switch arm or w iper43 is immediately adthat the closing of the circuit of the battery 26 through the ringing cut-ofl' relay causes an operation of this relay R and establishes a talking circuit between the called and calling stat-ion. Therefore,'as the dial contacts 107 alternately open and close, a circuit may be traced from the battery 15a, through one winding of the line relay 15, wire 13, contacts107 and the calling station to the wire 12 and through the second winding of the line relay 15 to the battery 15m The interruption of the battery current at the dial springs 107 sets up in the highly inductive windingsofthe line relay a discharge 'or kick employed in the operation of the apparatus for operation of the number wheel, energizing the magnet 63 through a circuit which maybe traced as follows From line relay 15 through the line 13, line condenser108, contacts 38 and 28, wire 29, wiper 17, wire 18, *condenser 18a, wire 86, the windings of the relay 78, wire 85, wire 320,, contacts 34 and 37 and line condenser 109 to the line relay 15. This energizes the polarized relay 78 and the contacts and 91a are thereby brought into engagement, establishing a" circuit as follows: From battery 77 through the wire 92, the seventh pair of contacts, wires 94 and 93, windings of the magnet 63 and wire 95 to the battery 77. At the same time, current V I will pass from the battery through wire 92, through the wire 96 to electro-magnet 49 and from this electro-magnet through wires that the inductive impulses will come in series corresponding, to the number of times 5 the dial contacts 107 are opened and the electro-magnet 63., since it is of the ordinary type, will attract its armature once for each i 97 and 95 to the battery. It willbe obvious From thepositive terminal of the local bat V tery 77 through the wire 98, thecontats of the twelfth pair and wiper 43, wire 99, coil 67 and return wires 97 and 95 to the negative terminal of the battery. This causes the armature 68 to be attracted, with the result that the paper strip is forced into engagement with the type of the type wheels to print the registered number;

Operation of this armature 68 furthermore closes the contact springs 100 which then sets up a circuit as follows: From the positive terminal of the battery 77, through the wire 98, contact springs 100, wires lQl and 102 to the coils of release magnets 54 and 65. From the release magnet 54, current returns by way of wires'103, 97 and 95 to the battery, while from the coil of the; magnet (35, it returns by Way of the wires 94 and 95. With the armatures of these magnets attracted, the operating and holding pawls of the number wheels 57 and switch arm 43 or wiper are withdrawn, permitting these elements to return to their normal position through their bias springs 44 and .66. Movement of the wiper 43 from the twelfth contacts opens the circuit of the clectromagnet 67, permitting the armature (38 to fall and thus opening the circuit of the release magnets 54 and 65 at the contacts 100. The delayed release provided by equipping these magnets with copper collars will prevent the re-engagement of the pawls controlled thereby until the several parts have returned to their normal positions. As the armature bar 68 resumes its normal position, the pawl 79 carried thereby advances the paper strip feeding rolls 71- to present a clean surface for the next printing opera-' tion. Attention is directed tothe fact thatattraction of the armature opens the cir- Qcuit which is normally established by engagement of-the wiper 43 with the contacts of the sixthpair, so that there is no danger I swered. wiper 43 will be'in engagementywith one of of operation resulting from the temporary engagement of, the wiper with .these contacts as it returns to its normal position..

It will'be obvious that under some circumstances, a printingoperation will be" partially completed when the-phone is an- Under these circumstances, the

the seventh to eleventh pairs of contacts. Where thisis the case, the removal ofthe receiver from'the book 23 closesthe circuit,

introducing direct current from battery 6 in the completed call line and this current" must complete its path through the coil of the release relay magnet 7 9.

Attraction of,the armature of this relay closes the contacts 104, thereby completing a, shunt aboht the contacts 100 through the wires 106 and 105 and including wires 94 and 95 and battery 77, so that thecircuit of the release magnets is completed and the several parts restored to their normal positions. Under other circumstances, a party having started the registration of a number may make an error in this number, necessitating a re-settlng of the apparatus. Th1s may be accomplished by the calling stationhanging up and then remaking the call. The

110. The ratchet 59 of each wheel has a vacant space which aligns with the operating pawlwhen this symbol is aligned for printing so that the wheel cannot be further advanced. Therefore, each ringing o eration will'advanc'e the type wheels until t e symbol 110 has been aligned for printing when it may advance no further. At the'completion of each ringing interval, the switch arm 43 will be advanced. This operation will continue until the twelfth pair of contacts has been short-circuited and a the number printed and the several parts returned to -the1r normal positions. The ringing opera tions will then continue until the sixth pair of contacts is reached by the arm 42 when the-call will be carried through as above.described. It will be obvious that the above conditions will obtain if, for any reason, registration of a callis abandoned before'its completion.

Attention is called to the fact that the polarized relay in my system is of particular usedbecause of its 'sensitiveness to dial impulses. These impulses will pass to the called station when the dial is operated.

importance and that it is necessary to be crate the ring-cut-olf relay and stop ringing operations. The line relay 15, by its operation under control of the dialing device at the calling station after the completion'of the call, is the means for providing, and

from the highly con uctive windings of this relay will be transmitted from the coupling condensers 108 and 109 to the line of the called station, operating the polar relay to cause it to close its contacts at every impulse. Thus the polarized relay in my system is the controlling member of the recording system, as all impulses from the line are" received by this relay and this controls the recording mechanism. In my system, the se- '15 quence switch, the circuit of which is controlled by the polarized relay, advances step by step until the wipers reach the 7th pair of contacts. This places the polarized relay windings across the line. The placing of the relay windings across the line causes the ring cut-off relay 21 in the connector switch to pull up its armature and cut off the ringing current to the called telephone. It will also cause the back bridge. to reverse the battery in the calling loop. The placing of the polarized relay across the line to direct battery, will cause the polarized relay to close its contacts in the opposite direction to what they were before due, to the fact that the polarity of the battery is reverse to that of the signalling impulses. This will cause the sequence switch magnet 49 to pull down its armature. The pulling down of this armature will open a pair of contacts 52 which breaks the direct battery circuit through the polarized relay which then returns to a neutral position, opening the circuit through the windings of the sequence switch magnet coil 49, allowing the armature to fall back, advancing the wiper arm 42 one stepand opening the circuit, removing the direct current path. When the wiper advances, it engages with the first recording bank contact, that is, the seventh pair of contacts, ready to record any impulses delivered to the recording mechanism by the polarized relay which receives these impulses from the line relay 15. The polarizedrelay is the controlling member of the-device, therefore, being first controlled by the ringing current to advance the wiper of the sequence switch 4 to a position on the 7th pair of contacts where it completes a circuit to cause the cessation of ringing operations and at the same time sets up a condition as outlinedabove to cause them to advance themselves, then removing this condition and thus clearing the line. It'will be seen from this description that the placing of the direct current path across the line is only momentary, thus leaving the line in a normal condition with the switches subject to release on the hanging up of the receiver by the calling subscriber. The operto cutting off the ringing current, also serves to connect the, calling subscriber to the called through, of course, the relay 15 and the coupling condensers 108 and 109. a My device' can be abandoned in any operated or partly operated condition and will restore itself to normal on the receipt of ringing current of an ensuing call, but during all this time, the line is absolutely clear. In addition to this feature, the switches will be released on the hanging up of the receiver by the calling party. 7

Since the construction hereinbefore set forth is capable of a certain range of change and modification without materially departing from the spirit of the invention, I do not limit myself to such specific structure except as hereinafter claimed.

I claim:

1. The combination with an automatic telephone system including the usual ringing apparatus and a talking circuit includ-,

ing means producing a series of current impulses at the called station upon operation of the dial switch of the calling station after the talking circuit is established, of recording apparatus including an element advancecl to recording position by said ourrent impulses, means operative after a predetermined number of operations of the ringing apparatus establishing the talking circuit and then connecting the recording apparatus thereto, means operated by the removal of the receiver of the called station releasing said means and said element of the recording apparatus to permit return thereof to normal position, and means acting on the second named means and the said ele- I ment to return them to normal position. released.

2. The combination with an automatic telephone system including the usualringing apparatusand a talking circuit including means producing a series of current impulses at the called station upon operation of the dial switch of the calling station after the talln'ng circuit is established, of recording apparatus including a plurality of elements advanced to recording position by said current impulses, means operative after a predetermined number of operations of the ringing apparatus establishing the talking. circuit and then consecutively connecting the elements of the-recording apparatus thereto, and meansv connecting said recording apparatus for operation by said ringing means whereby the sequence of operations may be completed through said ringing" mg means producing a series of current im- .pulses at the called station upon operation 1 of the dial switch of the calling station after the talking circuit is established, of recording apparatus including a plurality of elements advanced to recording position by said current impulses, or by a ringing impulse, and means operative after a predetermined number of operations of the ringing apparatus establishing thetalking circuit and then consecutively connecting the elements of the recording apparatus thereto.

4. -The combination with an automatic telephone system including the usual ringing apparatus and a talking circuit including means producing a series of current impulses at the called station upon operation of the dial switch of the calling station after the talking circuit'is established, of record- 4 ing apparatus including a plurality of elements advanced to recording position by said current impulses, a switch controlling the operation of said recording elements, means glving bias to the switch and recording elements normally maintaining them in one position, means for advancing said switch by a predetermined number of operations of the ringing apparatus to close the talking .,circuit and connect the first of the elements of the recording apparatus thereto, said means being operable by said current impulses to further advance the switch and consecutively connect the remaining elements of the recording apparatus thereto,

and means releasing the switch and recording elements upon completion of the recording operation.

5. The combination with an automatic telephone system including the usual ringing apparatus and -a talking circuit including means producing a series of current impulses at the called station upon operation of the dial switch of the calling station after the talking circuit is established, of recording apparatus including a plurality of elements advanced to recording position by said current impulses, or by ringing impulses, means for returning said elements to a normal position,means for recording the positions of said elements after a recording operation, and'means operative after a predetermined number'of operations of the ringing apparatus establishing the talking circuit, vthen selectively connecting the elements. of

the recording apparatus thereto, and finally operating said recording means and releasing the elements to permit return thereofzto a normal position. v r 6. The comblnation with an automatic telephone. system including the usual ringing apparatus and atalking circuit including means producing a series of current impulses at the called staftion upon operation of the dial switch of the calling station after the talking circuit isestablished, of recording apparatus including a pluralityof elements advaiicedtorecording position by said current impulses or by' ringing, impulses, means for returning said elements to a normal posit-ion, means for recording the positions of said elements after a recording operation, and means operative after a predetermined number of operations of the ringing apparatus establishing the talking circuit, then selectively connecting the elements of the recording apparatus thereto, and finally operating said recording means and releas ing the elements to permit return thereof to normal position, said recording elements when operated under the influence of a ringing impulse giving an indication of such operation. a

7. The combination with an automatic telephone system including the usual ringing apparatus and a talking circuit including means producing a series of current impulses at the called station upon operation of the dial switch of the calling station after thetalking circuit is established, of a plurality of printing wheels and means for feeding' a paper strip thereby, electro-magnetic means for advancing the printing wheels and a sequence switch acting after a predetermined number of operations of the ringing apparatus to consecutively establish I ing means producing a series of'current im-f pulses at the called station uponoperation of the dial switch of the calling station after the talking circuit is established, of a plurality of printing wheels andmeans for feeding a paper strip thereby, electro-magnetic means for advancing the printing wheels, a sequence'switch actingatter a predetermined number of operations of the ringing apparatus to consecutively establish the talking circuit, connect the operating means of t e printing wheels to said talking circuit for operation thereby and then force the paper strip into',engagement with the,"

printing wheels and release said? printing wheels andsequence switch to permit return f thereof to normal position, said electro-magnetic means and sequence switch being operable by a ringing impulse, means limiting operation of the printing wheels when actuatedby a ringing impulse, and means upon theprinting wheels aligning with the paper strip 'for contact thereon for indicating the operation of said printing wheels through a ringing impulse. 1

9. The combination with an automatic telephone system including the usual ringing apparatus and talking circuit, of a polarized relay producing a series of current impulses at the called station upon the production of impulses at the calling station after the talking circuit is established, a

' recording apparatus including a switch having a wiper advanced to recording position step by step by said ringing current 1111- pulses, the wiper operating after a predetermined number of operations of the ringing apparatus to establish the talking circuit and then connecting the ringing apparatus thereto, and means operated by the removal of the receiver of the called station releasing said recording apparatus including said switch wiper to permit the return thereof to normal position.

10. The combination with an automatic telephone system including the usual ringing apparatus and a talking circuit including a polarized relay adapted to produce a series 'by the removal of the receiver of the called station, and meansoperated by said release relay when energized causing the release of the recording mechanism including said switch wiper and permitting their return to their normal position.

11. In an automatic telephone system embodying the usual ringing apparatus, and

' talking circuit and including a line relay,

associated condensers and means at one station for causing signalling current impulses in the line relay, a recording mechanism at the other station, a polarized relay controlling the recording mechanism and electrically connected to the condensers and receiving signal impulses from the line relay through said condensersand a local battery for the recording mechanism the polarized relay having an armature acting when shifted in either direction from a neutral position by the polarized relay to connect the local battery with the recording mechanism.

12. In an automatic telephone system embodying the usual ringing apparatus and talking circuit and including a line relay, associated condensers and means at one station for causing signalling current impulses in the line relay, a polarized relay at the other station electrically connected to the condensers and receiving signalling impulses therefrom, a recording mechanism including a sequence switch having a wiper, a local battery, an armature for the polarized relay normally in a neutral position but shiftable in either direction, an operating magnet for the sequence switch, the energizing of the polarized relay causing its armature to connect the local battery in circuit with the operating magnet of the switch, means for energizing said polarized relay from the ringing apparatus during the ringing period to advance the wiper of the sequence switch one step for each ring, meansoperating after a predetermined number of rings, energizing the polarized relay from said condensers to thus cause the polarized relay armature to close the circuit from the local'battery-from the operating magnet of the sequence switch and recording mechanism controlled by said sequence switch and polarized relay.

13. In an automatic telephone system em bodying the usual ringing apparatus, and a talking circuit and including a line relay, associated condensers, and means at one station for causing signalling current impulses in the line relay, a' polarized relay at the other station electrically connected to the condensers and receiving signalling impulses therefrom, a sequence switch and step by step operated recording mechanism controlled partially by said sequence switch, means acting to step up the wiper of the sequence switch one step for each series of impulses received by the polarized relay, means acting to transmit an impulse to the recording mechanism for each impulse received by the polarized relay, and means acting when the receiver is taken ofl the called line or when the wiper has reached the end of its movement in one direction to release the wiper and recording mecha;

nism, cause the return of the wiper and recording mechanism to their 1n1t1al positions and clear the line.

14; In an automatic telephone systemembodying the usual ringing apparatus and talking circuit and including a line relay,

associated condensers, and means at one station for causing signalling current impulses in the line relay, means at the other station for recording said signalling impulses and including a polarizedrelay controlling said recording mechanism and receiving-signalling impulses from theline relay through said condensers.

In testimony whereof I. hereunto aifix my signature. 1

- HAROLD LYNWO OD WARWICK. 

